A common medical X-ray imaging apparatus includes; an overhead traveling system, in which an X-ray irradiation element, including an X-ray tube, is supported liftably (movable up-and-down) along the supporting post installed downward from a carriage, which is movable on the rail installed on the ceiling; a fixed system, in which the X-ray irradiation element, including an X-ray tube, is supported liftably along the supporting post installed on the floor nearby the table on which a subject is lying; and a round (movable) system, in which the X-ray irradiation element, including an X-ray tube, is supported liftably along the supporting post being hanged from the movable platform. Normally, the X-ray irradiation element, including an X-ray tube, is being hanged with at least two wire-ropes inside the supporting post in any X-ray imaging apparatus.
The X-ray irradiation element, including an X-ray tube, can be hanged with one wire-rope, but in such case, the diameter thereof must be essentially large due to a fatigue strength design-wise, and consequently, flexibility is lost due to such large diameter of the wire-rope, so that at least two flexible wire-ropes having an adequate diameter are commonly used due to restriction of a pulley and an apparatus size.
In such X-ray imaging apparatus, a breaking wire detection mechanism that detects breaking of the wire-rope is equipped to prevent a falling-down incident of the X-ray irradiation element, including an X-ray tube due to breaking of the wire-rope. For example, relative to the overhead traveling system X-ray Imaging apparatus, the X-ray tube thereof is being hanged with a plurality of wire-ropes and the breaking of the wire-ropes is always monitored by the breaking detection mechanism and when the breaking detection mechanism detects breaking of the wire-rope, the breaking mechanism locks the lifting of the X-ray irradiation element, including an X-ray tube (refer to the Patent Document 1).